Apparatus for monitoring a measurement transmitter of a field device

• US 7,345,581 B2
• Filed: 04/02/2004
• Issued: 03/18/2008
• Est. Priority Date: 04/02/2003
• Status: Expired due to Fees

• Current Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Original Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Inventors: Matt, Christian
• Primary Examiner(s): Pope; Daryl C
• Application Number:
  US10/815,939
• Publication Number:
  US 20050035867A1
• Time in Patent Office: 1,446 Days
• Field of Search: 340/539.26, 340/539.24, 340/529.28, 340/539.27, 340/568, 340/601, 340/602
• US Class Current: 340/539.26
• CPC Class Codes: G01D 1/18 with arrangements for signalling that a predetermined value of an unspecified parameter has been exceeded G01D1/14 takes precedence
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01F 1/8431 electronic circuits
• CPC Class Codes: G01F 1/8477 with multiple measuring conduits
• CPC Class Codes: G01F 15/024 involving digital counting

Abstract

An apparatus for monitoring a measurement transmitter of a field device determining and/or monitoring a physical and/or chemical process parameter, wherein at least one sensor is provided inside the a housing, in which the transmitter is arranged. The sensor determines the temperature and relative humidity in the housing over a period of time in predetermined intervals, and a control-/evaluation-unit is provided, which, on the basis of the measured temperature and relative humidity, determines the absolute humidity and/or the dewpoint in the housing of the transmitter, and issues and alarm when the absolute humidity and/or the dewpoint in the housing of the transmitter reaches a critical value.

Claims

1. An apparatus for monitoring a measurement transmitter of a field device the field device performing one of:

determining and monitoring one of;

a physical and chemical process parameter, the field device including a sensor and a transmitter, the apparatus, comprising;

a housing;

at least a second sensor provided in said housing for determining the temperature and relative humidity in said housing over a period of time in predetermined intervals; and

a control-/evaluation-unit, which, on the basis of the determined temperature and relative humidity, determines the absolute humidity and/or dewpoint in said housing, and issues an alarm when the absolute humidity and/or dewpoint in said housing reaches a critical value, wherein;

the sensor of the field device is connected in close proximity to said housing; and

the transmitter of the field device is mounted on the sensor.

2. The apparatus as claimed in claim 1, wherein:

said at least said second sensor for measuring temperature and relative humidity is an SMD-semiconductor-sensor.

3. The apparatus as claimed in claim 1, further comprising:

a memory unit in which a point, or range, of operation for the temperature is predetermined.

4. The apparatus as claimed in claim 1, further comprising:

an input unit, by means of which the point, or range, of operation for the temperature can be entered.

5. The apparatus as claimed in claim 1, wherein:

said control-/evaluation-unit sets the critical value, such that, in the case of the lowest possible operating temperature, no condensate forms in said housing.

6. The apparatus as claimed in claim 1, wherein:

said control-/evaluation-unit sets an alarm when a predetermined tolerance-value near the critical value is reached or subceeded.

7. The apparatus as claimed in claim 6, wherein:

said control-/evaluation-unit, on the basis of historical information, issues information on when the critical value is predicted to be reached.

8. The apparatus as claimed in claim 1, wherein:

said housing is mounted on the sensor of the field device.